Journal Articles - UP - MSI
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- Latitudinal variation in growth and survival of juvenile corals in the West and South PacificNozawa, Yoko; Villanueva, Ronald D.; Munasik, Munasik; Roeroe, Kakaskasen Andreas; Mezaki, Takuma; Kawai, Takashi; Guest, James; Arakaki, Seiji; Suzuki, Go; Tanangonan, Jean J. B.; Ang, Put O.; Edmunds, Peter J. (Springer, 2021-08-18)Reef-building corals are found across > 30° of latitude from tropical to temperate regions, where they occupy habitats greatly differing in seawater temperature and light regimes. It remains largely unknown, however, how the demography of corals differs across this gradient of environmental conditions. Variation in coral growth is especially important to coral populations, because aspects of coral demography are dependent on colony size, with both fecundity and survivorship increasing with larger colonies. Here we tested for latitudinal variation in annual growth rate and survival of juvenile corals, using 11 study locations extending from 17° S to 33° N in the West and South Pacific. Regression analyses revealed a significant decline in annual growth rates with increasing latitude, whereas no significant latitudinal pattern was detected in annual survival. Seawater temperature showed a significant and positive association with annual growth rates. Growth rates varied among the four common genera, allowing them to be ranked Acropora > Pocillopora > Porites > Dipsastraea. Acropora and Pocillopora showed more variation in growth rates across latitudes than Porites and Dipsastraea. Although the present data have limitations with regard to difference in depths, survey periods, and replication among locations, they provide evidence that a higher capacity for growth of individual colonies may facilitate population growth, and hence population recovery following disturbances, at lower latitudes. These trends are likely to be best developed in Acropora and Pocillopora, which have high rates of colony growth.We appreciate volunteers, students, and assistants for data collection. Y.N. especially thank H.-S. Hsieh and C.-H. Liu for data measurement, and V. Denis for his comments on the manuscript. Comments from two anonymous reviewers improve our manuscript greatly. The study was funded by the thematic research grant of Academia Sinica (23-2g) and an internal research grant of Biodiversity Research Center, Academia Sinica to Y.N. The Okinawa survey was partly supported by the Japan Society for the Promotion of Science through NEXT Program #GR083. Temperature data for the Okinawa site were provided by the coral reef survey of Monitoring Sites 1000 Project, operated by the Ministry of the Environment, Japan. Temperature data for Moorea were provided by the Moorea Coral Reef LTER, funded by the US National Science Foundation (OCE-0417412).
- Zooxanthellae diversity and coral-symbiont associations in the Philippine archipelago: specificity and adaptability across thermal gradientsTorres, Andrew F.; Valino, Darryl Anthony M.; Ravago-Gotanco, Rachel (Frontiers Media SA, 2021-10-20)Prolonged thermal stress and high levels of solar irradiance can disrupt the coral-algal symbiosis and cause bleaching and lowered overall fitness that lead to the likely death of the cnidarian host. Adaptive bleaching and acclimatization of corals, which posits bleaching as an opportunity for the coral host to switch its currently susceptible endosymbionts to more stress-tolerant taxa, offers hope for survival of reefs amid rapidly warming oceans. In this study, we explored the diversity and distribution of coral-zooxanthellae associations in the context of geospatial patterns of sea surface temperature (SST) and thermal anomalies across the Philippine archipelago. Thermal clusters based on annual sea surface temperature means and each site’s frequency of exposure to heat stress were described using three-decade (1985–2018) remotely sensed data. Haphazard sampling of 628 coral fragments was conducted in 14 reef sites over 3 years (2015–2018). Using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting and sequencing of the zooxanthellae ITS2 region, we characterized endosymbiont diversity within four reef-building coral families across archipelagic thermal regimes. Consistency in dominant Symbiodiniaceae taxon was observed in Acropora spp., Porites spp., and Heliopora coerulea. In contrast, the family Pocilloporidae (Pocillopora spp., Seriatopora spp., and Stylophora pistillata) exhibited biogeographic variability in zooxanthellae composition, concordant with inferred occurrences of sustained thermal stress. Multivariate analyses identify two broad Pocilloporidae clusters that correspond with mean SST ranges and frequency of exposure to bleaching-level thermal stress which are largely supported by ANOSIM. Differences in zooxanthellae assemblages may reflect host-specific responses to ecological or environmental gradients across biogeographic regions. Such patterns of variability provide insight and support for the adaptability and potential resilience of coral communities in geographically and oceanographically complex regions, especially amidst the increasing severity of global and local-scale stressors.This paper is dedicated to the late Ronald D. Villanueva whose contribution to the project during its inception has been invaluable. The authors thank Patrick R. Pata and the reviewers LE and RC-T for their helpful comments and suggestions, and acknowledge Hazel O. Arceo, Cesar L. Villanoy, and Maria Lourdes San Diego-McGlone for their support of this study. Eileen Peñaflor and Mariana Soppa shared key knowledge in processing satellite products. Mikhael Tañedo, Romer Albino, Emmeline Jamodiong, David Siquioco, Lovely Heyres, Rhea Luciano, Joey Cabasan, Frederico Sabban, Geminne Manzano, Clairecynth Yu, Joyce Velos, Joseph Garcia, Robert Casauay, Maryjune Cabiguin, Macy A onuevo-Arcega, Ariel Loja, Jerome Genilan, Amabelle Go, Jamie Dichaves, Elaine Saniel, and Miledel Quibilan assisted with field collections. Supporting hard coral data were provided by the DOST-PCAARRD NACRE Program and the DENR-BMB WPS and SECURE Philippine Rise Projects. This is MSI contribution number 486.
- Characteristics of marine heatwaves in the PhilippinesEdullantes, Brisneve; Concolis, Brenna Mei M.; Quilestino-Olario, Raven; Atup, Dale Patrick D.; Cortes, Aiza; Yñiguez, Aletta T. (Elsevier, 2023-09)Marine Heatwaves (MHWs) are prolonged, discrete, and anomalously warm events, which have recently gained global attention due to their far-reaching effects and reported impacts. Although intensive studies have been carried out at global and regional scales, these events remained understudied in the Philippines – a country with high marine biodiversity. The Philippines is highly vulnerable to the impacts of these extreme events as it lies in the western boundary of the Pacific that is considered as a hotspot for MHWs. The present study used multi-year climatic sea surface temperature (SST) record to detect MHWs in the Philippines. The detected events were then characterized using the standardized metrics. Linear trend analysis was conducted to determine the magnitude and direction of the change of the MHW metrics over time. Decadal trend revealed that MHWs in the Philippines significantly increased from seven MHWs in the 1980s to 37 MHWs in the last decade. Moreover, increased duration was remarkable in 2020 with 276 MHW days. MHW frequency and duration were increasing at a rate almost twice as its neighboring waters. Intensities did not significantly increase with time, but the highest SST anomaly is associated with El Niño Southern Oscillation. Furthermore, the eastern and western region of the Philippines is vulnerable to MHWs, but hotspots are mostly confined in the West Philippine Sea and western tropical Pacific. An in-depth investigation of the drivers of MHWs is recommended to understand the physical mechanisms of the development of these extreme thermal events in the Philippine seas. The findings have significant implications for coastal marine resource management, highlighting the need for adaptive management strategies and increased monitoring and research efforts to mitigate the impacts of MHWs on marine ecosystems and local economies in the Philippines.
- Co-occurrence of a marine heatwave and a reported tomato jellyfish (Crambione mastigophora Maas, 1903) bloom in March 2020 at El Nido, Palawan, PhilippinesQuilestino-Olario, Raven; Concolis, Brenna Mei M.; Atup, Dale Patrick D.; Cortes, Aiza; Yñiguez, Aletta T.; Edullantes, Brisneve (The Plankton Society of Japan/The Japanese Association of Benthology, 2023-05-31)Globally, observations on marine species during marine heatwaves (MHWs) help outline the scope of the MHW’s possible biological effects. In line with this effort, this paper presents a 2020 MHW that coincided with a reported ‘tomato jellyfish’ (Crambione mastigophora Maas, 1903) bloom on 23 March 2020 in the Corong-Corong Bay of Palawan, Philippines. Detecting a moderate MHW from 21 March to 04 April 2020, the analysis of sea surface temperatures revealed that most areas surrounding the bloom site attained their peak positive anomalies on the same day as the reported bloom. Certain physical mechanisms present in the first quarter of 2020 may have played a role in the occurrence of both events: the presence of cyclonic eddies and parallel monsoonal winds alongshore can induce upwelling which promotes biological productivity in surface waters, while the observed weakening of winds have been associated with anomalous warming of the sea surface. Further studies are still highly recommended to determine the exact causes of the jellyfish bloom and what conditions make it more likely to happen during MHWs. However, if the C. mastigophora is hypothetically able to continually bloom amidst warming temperatures, the increasing trend of MHW frequency and intensity in the West Philippine Sea (where the reported bloom site is situated) may consequently yield more future co-occurrences. This paper aims to hopefully contribute to the existing knowledge of possible biological impacts associated with extreme marine events, especially in the Philippine context where both jellyfish blooms and MHWs are understudied.The authors would like to express sincere gratitude to the anonymous reviewers whose comments and suggestions helped improve and clarify this manuscript. The authors would also like to thank Mr. Alimar Amor for his permission on the still photos in Figs 1c and 1d from his recorded jellyfish bloom video on 23 March 2020. This paper is also made through the funding of DOST̶ Philippine Council for Industry, Energy, and Emerging Technology Research and Development under the Survey of Heatwaves in the Philippine Seas project (DOST Project No. 9615).
- Natural and anthropogenic climate variability sgnals in a 237-year-long coral record from the PhilippinesInoue, Mayuri; Fukushima, A.; Chihara, M.; Genda, A.; Ikehara, Minoru; Okai, T.; Kawahata, Hodaka; Siringan, F. P.; Suzuki, Atsushi (American Geophysical Union, 2023-11-29)Both proxy and model studies conducted to understand anthropogenic warming have revealed historical variations in sea-surface temperature (SST) since the industrial revolution. However, because of discrepancies between observations and models in the late nineteenth century, the timing and degree of anthropogenic warming remain unclear. In this study, we reconstructed a 237-year-long record of SST and salinity using a coral core collected from Bicol, southern Luzon, Philippines, which is located at the northern edge of the western Pacific warm pool. The SST record showed volcanic cooling after several volcanic eruptions, including the 1815 Tambora eruption, but the pattern of change differed. Decadal SST variations at Bicol are connected to Pacific Decadal Variability (PDV). Therefore, it is suggested that the PDV conditions at the time of the eruption may have influenced marine conditions, such as the degree and duration of cooling and/or salinity, after the eruptions. Although there were discrepancies in SST variations among the modeled, observed, and proxy SST data from the late nineteenth to early twentieth centuries, SST data from the late twentieth century showed globally coherent anthropogenic warming, especially after 1976. In particular, summer SST in the northwestern Pacific has become more sensitive to anthropogenic forcing since 1976.